JP2002337320A - Head assembly method for line type inkjet printer - Google Patents

Abstract

(57) [Problem] To form a line type ink jet printer by alternately arranging three or more matrix type ink jet heads (hereinafter referred to as MIJ heads) of a unit for maintenance and replacement, when a print width defect and a head seam occur. Avoid printing irregularities. SOLUTION: In the line type ink jet printer,
The MIJ heads 30 in the maintenance and replacement unit are arranged in two rows in the upper and lower rows in the paper feeding direction to cover all the dots in the digit direction printing area.
By using the mounting holes 32 for the stop fitting, the printing is successively assembled at the reference dimensional position to avoid printing defects due to the accumulation of tolerances. The even-numbered MIJ heads 30 in the lower row use the mounting holes 33 which are one dot loose. And the adjacent M
Printing irregularities at seams between the IJ heads 30 are avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembling method and an adjusting method for fixing a matrix type ink jet print head at a predetermined position to construct a line type ink jet printer which covers all dots in a printing area in a digit direction. About.

[0002]

2. Description of the Related Art Conventionally, in an on-demand type line-type ink jet printer, about 1600 (printing width 9 inches, dot interval 18
It has been proposed to arrange nozzles of 0 dpi (dot / inch) in one row. However, even today, 160
It is difficult to stably maintain the ejection characteristics of zero nozzles, and it has not been practically used yet. Further, even if the ink jet head is practically used successfully, when one nozzle breaks down during use and the nozzle is replaced, the entire ink jet head must be replaced, which is very uneconomical. Further, to arrange the nozzles in one row, 18
The mounting density of 0 dpi is the limit, but at this mounting density, the space such as the ink passage is narrowed, and high-viscosity ink cannot be ejected. Therefore, there is a method of configuring a line array ink-jet printer using a plurality of ink-jet heads. In this case, when connecting the ink-jet heads, it is necessary to perform alignment with an accuracy of one dot, which is complicated. It was very difficult to easily perform alignment without using an apparatus.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the efficiency of replacing individual ink jet heads in a line type ink jet printer using a plurality of ink jets.

Further, when a line type ink jet printer is constructed by combining three or more ink jet heads, errors in assembling the ink jet heads accumulate and the print width becomes narrower by about 1 mm, or conversely, 1 mm. An assembly adjustment method that can prevent problems such as overprinting and exceeding the pre-printed form ruled line frame, and also prevent problems such as noticeable white streaks and dot overlap at the joint between adjacent matrix type inkjet heads. The challenge is to provide

[0005]

In order to achieve the above object, according to the present invention, in a line type ink jet printer in which a plurality of ink jet heads are arranged, a mounting hole for mounting an ink jet head has a diameter in a girder direction. The diameter d to be fitted or the diameter D larger than the diameter d by one dot interval.
In the mounting hole, the row direction is longer than the column direction,
In order to have the same diameter in the row direction, the diameter d and the diameter D are set in the girder direction, and the mounting holes are machined one by one in the upper and lower directions. The inkjet head to be accurately mounted at the reference position by using the mounting hole of d and the lower part of the inkjet head is adjusted by using the mounting hole of diameter D in the girder direction so that the joint with the upper inkjet head is inconspicuous. Assemble.

In the present invention, the ink jet heads on both sides of the ink jet head to be adjusted print all dots at once, and the ink jet head to be adjusted has one dot at both ends unprinted and the remaining ink jet head unprinted. It has a test print function with a test print pattern that prints all dots simultaneously.

Further, when the joint between the inkjet head to be adjusted and the inkjet heads adjacent to the inkjet head cannot be completely adjusted, the inkjet head to be adjusted is attached at an angle.

[0008]

FIG. 1 shows an on-demand type ink ejection mechanism used in the present invention.

When a drive signal is output from a matrix type ink jet print head (hereinafter, referred to as MIJ head) control circuit 20 in accordance with an instruction from the printer control circuit 21 and transmitted to a piezoelectric drive element drive circuit (hereinafter, referred to as PZT drive circuit) 19, an electrode is formed. A voltage is applied to a piezoelectric driving element (hereinafter, referred to as PZT) 13 via 17 and 18. At this time, PZ
T13 is displaced to give displacement to the diaphragm 7, and the ink in the ink chamber 3 is ejected from the nozzle 1. The restrictor 5 is a passage for replenishing the ink chamber 3 with the ink from the common ink passage 10, but is formed as a narrow passage to prevent a backflow at the time of ink ejection.

FIG. 2 is a view of the MIJ head as viewed from the ink jetting surface side, and FIG. 3 is a view showing the mounting side of the MIJ head of FIG. In FIG. 2, the orifice plate 2
Above, nozzles are formed on a matrix, and the nozzle rows in the digit direction are shifted by 1/300 inch. Further, the mounting holes are machined so that the mounting holes of the diameter d and the diameter D constitute one set, and the mounting holes are arranged in the same direction in the row direction. here,
The row direction is the same as the paper feeding direction in FIG. 5, and the column direction is the direction in which the line heads are arranged, and is a direction perpendicular to the row direction.

FIG. 4 is a side sectional view of a line type ink jet printer used in the present invention.

In FIG. 4, printing paper 41 is supplied from a paper supply roller 42 and fed by a take-up roller 43 driven according to a paper feed signal of the printer control circuit 21.

FIG. 5 is a plan view of a line type ink jet printer as an example of the present invention.

In FIG. 5, the odd-numbered MIJ heads 30 counted from the left and right in the figure are arranged along the convex portions 35 (see FIG. 4) of the MIJ head mount base 45 in the row direction. Is determined.

At a reference position in the digit direction from the printing reference position,
The structure in which the MIJ heads 30 are accurately assembled prevents a printing width defect due to accumulated errors when a plurality of MIJ heads 30 are pressed to the left and assembled.

Next, a specific assembling method will be described.

In the figure, the first MIJ head 30 from the left
Is accurately attached to the position of the reference dimension of L1 from the printing reference position by using the MIJ head mounting hole 32 for the stop fit with the MIJ head mounting screw 34. Similarly, the third MIJ head 30 from the left is accurately attached to the position of the reference dimension of L3 from the printing reference position using the MIJ head attachment hole 32 for the stop fit with the MIJ head attachment screw 34.

Next, the even-numbered MIJ attached to the lower stage
The joint between the adjacent MIJ heads 30 is adjusted by a method of assembling the head 30 by adjusting the position in the printing girder direction.

That is, in the figure, the second MIJ head 30 from the left is attached to the reference position L2 using the MIJ head attachment hole 33 having the dimension D, and the test print is performed as shown in FIG. Adjust so that there is no joint failure with the MIJ head 30, and fix the MIJ head mounting screw 34.

FIG. 8 shows a modification of one embodiment of the present invention.

If the joint failure of the adjacent MIJ heads 30 cannot be suppressed within the adjustment range shown in FIG. 5, as a next best measure, the range of the dimensional difference between the diameter D and the diameter d when the even-numbered MIJ heads 30 are mounted. Inside, the MIJ head mounting screw 34,
The position of the MIJ head mounting hole 33 is mounted at a slightly inclined position. As a result, the printing width is slightly increased, and M
Fine adjustment of the IJ head 30 becomes possible.

Conventionally, in an on-demand type line type ink jet printer, about 1600 (print width 9 inches, dot interval 180 dpi) are provided in one IJ head.
It has been proposed to arrange (dot / inch) nozzles in one row. However, even at present, it is difficult to maintain high reliability with 1600 nozzles, and it has not been practically used yet. In addition, even if it is practically used, when one nozzle fails during use and is replaced,
The entire J head must be replaced, which is very uneconomical. Further, to arrange the nozzles in one row, 180 dpi
However, at this mounting density, a space such as an ink passage was narrowed, and high-viscosity ink could not be ejected.

On the other hand, each nozzle of the line type ink jet printer used in the present invention ejects at the drive timing shown in FIG. 7 so that each row of the even-numbered MIJ heads 30 attached to the lower part of FIG. And the nozzles of each row of the odd-numbered MIJ head 30 attached to the upper stage of FIG. 5 are controlled so that all dots are aligned on the same raster.

In FIG. 7, time t1 corresponds to the even-numbered MIJ
The time interval tp corresponds to the fourth row nozzle of the head 30,
This corresponds to the time required to move between the nozzle arrays. Time t2
Correspond to the fourth row nozzles of the odd-numbered MIJ head 30. Further, if the nozzles are mounted in eight rows according to the same principle, a resolution of 600 dpi is possible.

As described above, according to the present invention, the width of the common ink passage 10 and the like can be increased by manufacturing the MIJ head at 1/75 inch per row, substantially at 300 dpi, and the high viscosity (10 to 10 inches) can be obtained. It is possible to eject ink of 50 cPs (centi-poise). In addition, since the volume per nozzle can be widened, it is advantageous in ensuring the quality in manufacturing and ensuring the reliability when using the printer.

[0026]

As described above, according to the present invention,
When configuring a line-type inkjet printer, even if a failed nozzle occurs, it is economically inexpensive and can be easily replaced for maintenance, so that the practicality of the line-type inkjet printer can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an on-demand type ink ejection mechanism used in the present invention.

FIG. 2 is a diagram of the MIJ head used in the present invention as viewed from the ink ejection surface side.

FIG. 3 is a view of the MIJ head used in the present invention as viewed from the mounting side.

FIG. 4 is a cross-sectional view of a line-type inkjet printer showing an example of the present invention.

FIG. 5 is a plan view of a line type ink jet printer showing an example of the present invention.

FIG. 6 is a test print pattern for facilitating attachment adjustment of an even-numbered MIJ head used in the present invention.

FIG. 7 is a print timing chart for printing even-numbered MIJ heads and odd-numbered MIJ heads on the same raster used in the present invention.

FIG. 8 shows an even-numbered MIJ as a modification of the embodiment of the present invention.
Figure when mounting the head at an angle

[Explanation of symbols]

1 is a nozzle, 2 is an orifice plate, 3 is an ink chamber,
5 is a restrictor, 7 is a vibration plate, 10 is a common ink passage, 13 is a PZT (piezoelectric driving element), 16 is a support substrate,
17 is an individual electrode, 18 is a common electrode, 19 is a PZT drive circuit, 20 is an IJ head control circuit, 21 is a printer control circuit, 30 is an MIJ head, 31 is an MIJ head mounting surface,
32 is a MIJ head mounting hole, 33 is a MIJ head mounting hole, 34 is a J head mounting screw, 35 is a convex portion, 41 is printing paper, 42 is a paper supply roller, 43 is a take-up roller, 44 is an ink supply hose, 45 is a MIJ head mount base, and 46 is a printer stand.

Claims (3)

[Claims] 1. In the row direction, nozzles are arranged in a plurality of columns shifted by one dot in the column direction, and in the column direction, nozzles are arranged at intervals of dots by the number of columns in the row direction. Matrix inkjet print head
In order to cover all the dots in the girder direction printing area, at least three or more are used, and in a line type ink jet printer arranged alternately in upper and lower two stages, a mounting hole for mounting the matrix type ink jet print head is:
A set of a diameter d that forms a stop fit and a diameter D that is larger than the diameter d by one dot interval is processed one set at a time above and below the head so that the diameter becomes the same in the row direction. When installing the print head in the upper row,
Using a mounting hole having a diameter d to be a stop fit, the mounting is performed accurately at a reference position. When the matrix type inkjet print head is mounted on a lower row, a mounting hole having a diameter D is used to mount the matrix printing head on the upper row. A method for assembling a line type ink jet printer, wherein a seam with a liquid type ink jet print head is adjusted and attached. 2. A matrix-type inkjet print head on both sides of a matrix-type inkjet print head to be adjusted prints all dots at once, and a dot at the both ends of the matrix-type inkjet print head to be adjusted is unprinted. 2. The line type ink jet printer according to claim 1, wherein the printer has a test printing function provided with a test printing pattern for simultaneously printing all remaining dots. 3. When the matrix type inkjet print head to be adjusted and the joint between the matrix type inkjet print heads adjacent to the matrix type inkjet print head cannot be adjusted completely, the matrix type inkjet print head to be adjusted is inclined and attached. The line-type ink jet printer according to claim 1, characterized in that: